You need a tool to load .asi files. Silent's ASI Loader is a popular and reliable choice.
Copy the SAMPFUNCS.asi file into your main GTA San Andreas directory (where gta_sa.exe is located). You need a tool to load
The Ultimate Guide to SAMPFUNCS.asi: Power Up Your SA-MP Scripting supports multiple SA-MP versions including 0.3.7-R1
Ensure you have a clean installation of GTA San Andreas (v1.0 US/EU is highly recommended). You need a tool to load
The latest stable version, 5.7.1 , supports multiple SA-MP versions including 0.3.7-R1, R3-1, R5, and 0.3.DL.